Gas Turbine Rotor Blade Locking with Shield Slots
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing rotor blade arrangements in gas turbine engines often experience undesirable stress concentrations due to the asymmetrical placement of lock and load slots, which can lead to mechanical instability.
Innovation Solution
The introduction of shield slots with a depth less than lock slots and curved, part-circular designs that differ in radius from lock slots helps to mitigate stress concentrations by preventing accidental lock insertion and distributing mechanical loads more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If lock slots and load slots are placed asymmetrical in the rotor ledge, then the blade locking mechanism is simplified, but stress concentrations increase around the load slot
Solution Approach 1:
The patent applies asymmetry by introducing a shield slot on one side of the load slot but not the other, creating an intentionally asymmetric configuration that prevents accidental lock insertion while managing stress distribution through the asymmetric shield placement
Solution Approach 2:
The shield slot acts as an intermediary element between the load slot and the potential insertion path of locks. It serves as a mediating structure that blocks accidental lock insertion into the load slot while allowing the asymmetric configuration to maintain simplified blade locking functionality
2Reliability
If shield slots are introduced to prevent accidental lock insertion, then mechanical stability is improved, but the slot configuration complexity increases
Solution Approach 1:
The shield slot is designed with specific local characteristics - it has a different depth than the lock slot (extending less deeply into the ledge) and a different radius. This local differentiation allows the shield slot to perform its protective function without requiring a complete redesign of the entire slot configuration system
Solution Approach 2:
The slot system is segmented into functionally distinct components: lock slots for blade locking, load slots for blade loading, and shield slots for preventing accidental insertion. Each segment performs a specific function, allowing the overall system to achieve reliability through functional specialization rather than through uniform complex design
Data Source
Figure 1~2A
Figure 2B~4
AI summary
A rotor body rotates about an axis of rotation. A ledge provides a holding structure for holding blades. A plurality of blades are positioned beneath the ledge, load slot is sized to allow a mount portion of the blades to be moved radially inwardly of the ledge. The blades are moved circumferentially to have the mounted structure radially inwardly of the ledge. A lock slot is positioned on one circumferential side of the load slot. The lock slot is formed to receive a lock, and the lock is partially received within a portion of at least one of the blades, to lock the blades within the rotor, and a shield slot on a second circumferential side of the load slot. The shield slot is sized to be different from the lock slot such that a lock cannot be inadvertently positioned within the shield slot.